Process and machine for manufacturing paper bags



PROCESS AND MACHINE FOR MANUFACTURING PAPER BAGS Filed June 15, 1962 Feb. 18, 1964 R. F. SEARLE ETAL 15 Sheets-Sheet 1 INVENTORS. ROBERT F SEARLE, PAUL C. ROBINSON 8: BY WILLIAM A. JOHNSON Feb. 18, 1964 R. F. SEARLE ETAL PROCESS AND MACHINE FOR MANUFACTURING PAPER BAGS 15 Sheets-Sheet 2 Filed June 15, 1962 INVENTORS.

ROBERT SEARLE,

PAUL C BINSON 8: BY WILLIAM A. JOHNSON A TTORNEYS.

Feb. 18, 1964 R. F. SEARLE ETAL 7 PROCESS AND MACHINE FOR MANUFACTURING PAPER BAGS Filed June 15, 1962 15 Sheets-Sheet 3 E E p E E l 1-7616. 7 INVENTOR;

ROBERT F. SEARLE, PAUL c. ROBINSON :2. BY WILLIAM A. JOHNSON A TTORNEYS.

Feb. 18, 1964 R. F. SEARLE EIAL 3,

PROCESS AND MACHINE FOR MANUFACTURING PAPER BAGS 15 Sheets-Sheet 4 Filed June 15, 1962 FIG; 4.

INVENTORS. ROBERT F SEARLE,

PAUL C. ROBINSON 8 BY WILLIAM A. JOHNSON 774 yg av/ ATTORNEYS.

Feb. 18, 1964 R. F. SEARLE ETAL 3,121,374

PROCESS AND MACHINE FOR MANUFACTURING PAPER BAGS Filed June 15, 1962 v 15 Sheets-Sheet 5 INVENTORS. ROBERT E SEARLE, PAUL C. ROBINSON 3 BY WILLIAM A. JOHNSON Feb. 18, 1964 R. F. SEARLE ETAL 3, 7

PROCESS AND MACHINE FOR MANUFACTURING PAPER BAGS Filed June 15, 1962 15 Sheets-Sheet 6 r: in: i

Q N I; @"Mh Q W50 2 Wm W W gL I I I g N N 0.5 I M v 'l E Q [uh l R l w 1!! Q Q M Q i1 ml i 151W EEH Q INVENTORS. ROBERT F SEARLE, PAUL C. ROBINSON 8 BY WILLIAM A. JOHNSON ATTORNEYS.

Feb.- 18, 1964 R. F. SEARLE ETAL 7 PROCESS AND MACHINE FOR MANUFACTURING PAPER BAGS Filed June 15, 1962 15 Sheets-Sheet 7 INVENTORS. ROBERT F. SEARLE, PAUL C. ROBINSON 8 BY WILLIAM A. JOHNSON 111W. Jim

ATTORNEYS.

Feb. 18, 1964 R. F. SEARLE EIAL 3,

PROCESS AND MACHINE FOR MANUFACTURING PAPER BAGS Filed Jupe 15-, 1962 15 Sheets-Sheet 8 A66 F/Gu {ff V INVENTORS.

A54 ROBERT E SEARLE,

. PAUL c. ROBINSON 8- BY WILLIAM A. JOHNSON ATTORNEYS.

INVENTORS. ROBERT E SEARLE,

PAUL c. ROBINSON a BY WILLIAM A. aonusou R. F. SEARLE ETAL l5 Shegts-Sheet 9 S at Q QWU$ PROCESS AND MACHINE FOR MANUFACTURING PAPER BAGS Filed June 15, 1962 Feb. 18, 1964 @0 7fim 9% ATTORNEYS.

Feb. 18, 1964 R. F. SEARLE ETAL PROCESS AND MACHINE FOR MANUFACTURING PAPER BAGS l5 Sheets-Sheet 1O Filed June 15, 1962 Feb. 18, 1964 R. F. SEARLE ETAL 3,121,374

PROCESS AND MACHINE FOR MANUFACTURING PAPER BAGS 15 Sheets-Sheet 11 Filed June 15, 1962 ROBERT E SEARLE,

3 f M SH. JR W0 0 B MA WW4 am 7 Lil M Feb. 18, 1964 R. F. SEARLE ETAL 3,121,374

PROCESS AND momma FOR MANUFACTURING PAPER BAGS Filed June 15, 1962 15 Sheets-Sheet 12 F/GZ/6.

INVENTORS.

- ROBERT F SEARLE,

PAUL C.ROB|N$ON 8 BY WILLIAM A.JOHNSON ATTORNEYS.

Feb. 18, 1964 R. F. SEARLE ETAL PROCESS AND MACHINE FOR MANUFACTURING PAPER BAGS l5 Sheets-Sheet 13 Filed June 15, 1962 INVENTORS. ERT F SEARLE, L C. ROBINSON 8| A. JOHNSON r b m m ROB PAU BY WILLIAM A r ramvs rs.

Feb. 18, 1964 R. F. SEARLE ETAL 3,121,374

PROCESS AND MACHINE FOR MANUFACTURING PAPER BAGS l5 Sheets-Sheet 14 Filed June 15, 1962 v! m w MW E TEN M NRON 9 0 EASH T EWO T W B W A .0 F M w fi RMW w Feb. 18, 1964 R. F. SEARLE ETAL 3,121,374

PROCESS AND MACHINE FOR MANUFACTURING PAPER BAGS Filed June 15, 1962 15 Sheets-Sheet 15 INVENTORS.

ROBERT F SEARLE, PAUL C. ROBlNS 8: BY WIL LlAM A. JOHN N ATTORNEYS.

United States Patent 3,121,374 PROCESS AND MACHINE FGR MANUFATURIYG PAPER PAGE Robert F. Searle and Paul C. Robinson, Glens Falls, N.Y., and William A. Johnson, Rntland, Vt, assignors to Arlrell and Smiths, a corportm'on of New York Filed June 15, 1962, Ser. No. 262,912 20 Cliams. ((11. 93--22) This invention relates to a process and apparatus adapted for use in heat sealing the end closure of a paper bag provided with thermal plastic liner. In accordance with the present invention one end portion of a conventional bag tube with thermal plastic liner is opened into the form of an open box while one side of the box is held depressed so that the box may be advanced to cause a plow blade member to enter into the interior of the open box. The upright opposite side walls of the box are then collapsed downwardly in against the plow blade and folded so as to form an upstanding longitudinal fin running along the length of the enclosure. Thereafter, the bag is moved away from the plow blade and the upstanding fin is gripped by a pair of heat sealing jaws which apply heat and pressure to fuse adjacent portions of the thermal plastic liner in the fin. Following this operation, portions of the partially completed end closure of the bag tube are tucked down in between clamping jaws which force the end flaps in the end closure to stand upright. Thereupon the upright end flaps are each gripped by a pair of heat sealing jaws which apply heat and pressure to seal the thermal plastic liner in the flaps of the end closure. By sealing the thermal plastic liner in the fin and by providing cross seals in the end flaps of the closure, a complete seal of thermal plastic liner is achieved in the end closure of the bag to make it sift proof and prevent loss of finely divided material. The bag is completed by folding down the end flaps which are then pasted into the end closure of the bag. The pasted end flaps reinforce the heat seals of thermoplastic material in the end closure of the bag to strengthen the end closure which might otherwise fail under the weight of the packaged material. The apparatus of the present invention has great versatility and only very minor adjustments need be made in order to accommodate different size bag tubes. Details of the process and the details of a preferred form of apparatus for carrying out the process may be readily understood by reference to the drawings in which:

FIG. 1 is a side view of a preferred form of apparatus for carrying out the process of the present invention.

FIG. 2 is a perspective illustration of that portion of the apparatus of FIG. 1 which is employed for forming a box in one end of a bag tube.

FIG. 3 is a side view of the apparatus employed for forming the open box in one end of the bag tube.

FIG. 4 is a perspective side view of the apparatus employed for flattening the open box down against the bag tube.

FIG. 5 is a side view of one of the heat sealing jaw members of the apparatus of FIG. 1.

PEG. 6 is taken on line 6-6 of FIG. 5 to further illustrate the structure of the heat sealing jaw members shown in FIG. 5.

PEG. 7 illustrates one preferred way of supplying electric current to the heat sealing jaw members of FIG. 5.

FIG. 8 illustrates a transfer drum shown in the apparatus of FIG. 1.

FIG. 9 is a side view of the transfer drum of FIG. 8.

FIG. 10 illustrates apparatus used for tucking a portion of the bag tube down in between gripping jaws carried by the transfer drum of FIG. 8.

FIG. 11 is taken on line 1111 of FIG. l0.

3,121,374 Patented Feb. 18, 19%4 FIG. 12 is taken on line 12-12 of FIG. 11.

FIG. 13 illustrates the heat sealing jaws for sealing the thermoplastic liner in the end flaps of the bag.

FIG. 14 illustrates the details of the cutting blades associated with the heat sealing jaws for the end fiaps.

P16. 15 illustrates the bag tube transfer point in which the bag tubes with heat sealed end closure are transferred to a final drum for pasting down the end flaps to complete the end closure in the bag.

FIG. 16 is taken on line l616 of FIG. 15.

FIG. 17 illustrates the details of apparatus employed for pasting down the end flaps of the 'bag tube.

FIG. 18 illustrates the roll which applies paste to the heat sealed end flaps.

FIG. 19 illustrates additional apparatus employed for pasting down the end flaps in the closure of the bag.

FIG. 20 illustrates the arrangement of the heat seals in the end closure of the bag.

Turning now to FIGS. 1 and 20 of the drawings, 36 is a gusseted bag tube with an exterior paper ply 32 and an internal thermoplastic liner 34 which is glued to the paper ply. The tube has the usual gussets 36 and the usual longitudinal seam (not shown). One end portion of the bag tube is slit to form conventional end flaps 38 and 39 customarily employed in the socalled self opening square (SOS) type of bag. Such paper bag tubes with thermoplastic liner are conventional and well known in the art and the tube may be made in any desired manner. We prefer to heat seal the thermoplastic liner along the line of the seam in such manner as to form an inner tube of plastic material and in such case opposite edge portions of the paper ply are separately glued along the line of the seam to form an outer paper tube. This procedure for forming a separate inner and separate outer tube is described in United States Patent No. 2,875,673. Other conventional means may of course be employed for forming the seam in the bag tube.

In accordance with the present invention one end portion of the bag tube is opened and folded into the form of an open box and a portion of one side wall of the box is held depressed so that when the bag tube is advanced a stationary plow member may be caused to enter into the interior of the box. Thereafter, the box is collapsed and opposite side walls of the box are folded in against the plow member to form an upright longitudinal fin extending along a line approximately parallel to the seam of the tube.

In forming the longitudinal fin, a bag tube 30 is fed through advancing rolls 40 (FIG. 1) which feed the tube through a pair of conventional score rolls 41 which position three score lines 42, 44 and 46 (FIG. 26) across the width of the bag tube. These score lines are not essential but they do assist in folding the plies to form the end closure.

The scoring rolls feed the leading edge of the bag tube against a rotating drum 48 which carries a pair of movable fingers 50 (FIG. 2) which grip the leading edge of the end flap 38 in the bottom side wall of the bag tube in order to hold this portion of the side wall flat against the surface of the drum. Drum 48 rotates in counterclockwise direction (FIG. 2) and it carries the end portion of the bag tube into position under a bag end closure forming roll 52. Roll 52 rotates in clockwise direction (FIG. 2) and it carries a pair of gripping fingers 54- and 56 which move the gussets on opposite sides of the bag tube as shown in FIG. 3 to press the top fold of the gusset on opposite sides against the surface of the roll between the score lines 44 and 46. An additional pair of gripping fingers 58 each of which are located on opposite sides of drum 48 are also moved into the gusset on opposite sides of the bag tube under fingers 54 and 56 to press the bottom fold of the gusset on opposite sides of the bag tube against the surface of drum 48.

In the preferred form of structure shown a pair of wedge shaped cam plates 64) are supported independently of drum 48 in position to enter the gussets on opposite sides of the bag tube to cam the top fold of the gusset upwardly away from drum 48 to open the mouth of the bag tube in order to assist the fingers to grip the bag tube in predictable manner (FIG. 3). After the grippers are in place continued rotation of roll 52 causes grippers 54 and 56 to fold the gusset and side wall of the bag tube back over toward the exposed surface of the tube which results in forming the open box shown in FIG. 2. While not necessary it is preferred to hold the trailing end of the bag tube between scoring rolls 41 while the box is being formed. This tends to assist in manipulation of the paper.

A stationary plow member 62 is supported in position adjacent roll 52 and after the box is opened up by grippers 54 and 56 the bag tube is advanced by contined rotation of drum 48 so that plow member 62 enters into the interior of the box just after grippers 54 and 56 release the paper. Grippers 54 and 56 release the top fold of the gusset before the entire bottom surface of the open box is positioned against the surface of the top wall of the bag tube and as illustrated in FIG. 2 best results are achieved if the grippers are released when the line of the gusset wall along the bottom of the box still forms an obtuse angle with the outer edge of the gusset fold in the bottom wall of the bag tube. As the bag continues to move the plow member flattens the bottom of the box and end flap 39 against the surface of the top wall of the bag tube. At the same time a pair of guide rails or rods 64 and 66 contact the upright opposite side walls of the box 68 and 7 to fold the walls in against the plow member and form the upright substantially vertical longitudinal fin 72. (FIGS. 2, 4 and 20).

As best shown in FIG. 4, the end flaps 38 and 39 extend inwardly from the edges of the respective flaps to the score lines 44 in the top and bottom walls of the 'bag tube.

The slitting and scoring rolls and grippers and the means for actuating these members and feeding the bag tube to open one end of the tube into an open ended box are conventional and well known in the art. But the feature of holding flap 38 in depressed position against drum 48 and the feature of releasing grippers 54 and 56 before the bottom of the open box is folded down against the surface of the top wall of the gusseted bag tube to enable a stationary plow like member to enter into the interior of the partially formed box to flatten the bottom of the box against the surface of the top wall of the bag tube which results in forming the upright longitudinal fin is carried out in accordance with the present invention.

In the apparatus shown in the drawings drum 43 has four bag tube bottoming stations as indicated at 73 in FIG. 1. Each station is located ninety degrees apart so that four bag tubes may be processed for each single rotation of the drum. Since the slitting and scoring rolls and the grippers for opening the box of the end closure are conventional units customarily employed in bag making machines it is not deemed necessary to show or describe the details of the construction of these units or the cams employed for operating the units. As is customary in the art the position of these units on drum 48 may be adjusted to accommodate different size bag tubes and end closures.

As best illustrated in FIGS. 1 and after the longitudinal fin 72 has been formed the bag tube is advanced and the fin is moved away from plow member 62 until the middle of the length of the fin is approximately in a horizontal plane through the diameter of the drum. Drum 48 rotates through an angle of about ninety degrees between the time when grippers 54 and 56 start to open the box and the time when the middle of the length of the fin arrives in horizontal position which is the pick up position for transferring the bag tube to a fin sealing drum 76. Both drums 4S and 76 and roll '52 all rotate continuously during operation.

Fin sealing drum 76 is mounted on a hollow shaft 78 for continuous rotation in clockwise direction (FIG. 5). The drum carries five pairs of heat sealing jaw members 80 each of which are spaced an equal distance apart around the circumference of the drum. Each pair of heat sealing jaw members are positioned at a station as indicated at 79 in FIG. 1 but for convenience of illustration only one pair of heat sealing jaw members are shown. The diameter of drum 76 is greater than that of drum 48 and the speed of rotation is controlled in conventional manner so that the peripheral speed of drum 76 is approximately equal to that of drum 48. The space between each of the stations on drum 7 6 and drum 48 is so arranged that a pair of heat sealing jaw members St) arrive in the horizontal position to pick up a bag tube from each of the four stations on drum 43.

As best shown in F168. 5 and 6 each of the generally L-shaped heat sealing jaw members 3t) is provided with a removable jaw face 81 and each jaw member has a conventional heart sealing element 82 in the form of a removable c-antridge which generates the desired heat when supplied with electric current. The jaw members clamp the longitudinal fin of the bag tube and because of the heat and pressure the thermoplastic liner on opposite sides of the bag tube are fused together throughout the length of the fin. For example, a bag tube having a single outer ply of fifty pound super calendered bleached kraft paper with a cellophane liner coated with a heat fusible thermoplastic required a temperature of 270 F. and a jaw pres sure of five pounds for heat sealing the thermoplastic material. The temperature and pressure may of course be adjusted depending upon the type of thermoplastic material employed in the liner.

The second end of each of the generally L-shapcd jaw members carry a cam follower 84 for opening and closing the jaw members. Both jaw members are rotatively mounted on a shaft 86 of undercarriage 38 and each jaw member has a pair of springs 96 which are attached to the undercarriage by means of pins 92. The springs exert constant tension urging the jaw members to close and when closed the springs provide the pressure for fusing the thermoplastic liner in the longitudinal fin of the bag tube. A pair of fixed pins 94 are each mounted on opposite sides of undercarriage 88 in position to bear against the bottom of each of the L-shaped jaw members and the length of the pins is adjusted to hold the closed jaws in a predetermined position to insure uniform transfer of the bag tubes to drum 1%. Otherwise, if the tensional force of the two springs 90 is not exactly equal the jaw members will tilt and get out of alignment and interfere with orderly transfer of the bag tube to drum 1433. For convenience of illustration only one pin 94 is shown in the drawings.

The undercarriage 88 of the heat sealing jaw members is mounted on drum 76 by means of two links 96 positioned at one end of the jaw members and by means of two arms 97 positioned at the second end of the jaw members. The two links and arms are pivotally mounted on the undercarriage and on the drum and the arms are both keyed to a shaft 98 roita-tively mounted in drum 76. One arm 97 carries on cam follower extension 99 which mounts a cam follower 1% which is held in contact with the cam rail M2 by means of spring 1G4. Spring m4 constantly urges the leading end of the undercanriage (in the direction of rotation of rum 76) to tip down toward the drum and the trailing end of the undercarriage to move away from the drum. As a result spring 1% constantly urges arm 97 to rotate in counterclockwise direction FIG. 5 to hold cam follower *ltlil against the cam rail 1&2.

As best shown in FIG. 5 the heat sealing jaw members are of rectangular shape and when the rectangle of the jaw members is made lon enough to grip the longitudinal fin throughout its length a portion or" the jaw at each end of the rectangle extends out beyond the pitch diameter of the drum represented by the dotted line 105'. Because of this it is necessary to tilt the heat sealing jaw members to avoid contact with drum 43 as the jaw members move into the required position to grip the fin of the bag tube positioned on drum 48.

As the rectangular heat sealing jaw members approach the pick up point (FIG. 6) cam follower 1% and the extension 99 of arm 97 move in towards the center of he drum because of the depression 191 in cam rail 102.. This causes upper portion of arm 97 to move outwardly away from the center of drum 7 6 and as a result the rear of the jaw is moved outwardly away from the drum and the leading end of the rectangular jaw is moved in toward the center of the drum and inside the line of the pitch diameter 165. The jaw members then move into the pick up position and as the center of the jaw is advanced beyond the horizontal plane of the pick up point the cam follower 1% and the extension 99 of arm 97 are moved outwardly away from the center of drum 7 6 which causes the rectangular jaw to tilt in the opposite direction to bring the trailing end portion of the jaw inside the line of the pitch diameter. This tilting of the heat sealing jaw members is an important feature of the present invention which makes possible the use of rectangular heat sealing jaws which elfectively grip the entire length of the longitudinal fin of the bag tube. For the most efficient transfer of bag tubes from drum 4% to 76 these two drums are so mounted that a single horizontal plane may be passed through the center of both drums.

As the heat sealing jaw members 8%) move into the pick up position cam 84 on each jaw member rides up the incline 186 of a cam rail 1&7 which lifts the cams (FIGS. 5 and 6) to open the heat sealing jaws. When the middle of the rectangular jaw is approximately in line with the center of the fin of the bag tube cams ride down the inclines 1% of cam rai s 1437 under the tension of springs 9i} close the jaw members and apply pressure for gripping the fin. As the jaw members close on the fin grippers 5t and are released and the bag tube is released to the heat sealing jaw members which carry the bag tube around the drum for an angular distance of about two hundred and seventy degrees when the bag tube is again transferred to a drum 1&8 (PIG. l). A guide rail lltl assists in controlling the position of the body of the bag tube relative to the periphery of drum 75.

One preferred way of supplying electric current to the jaw members carried by drum 76 is illustrated in FIG. 7. As there shown electric current from a conventional control box 112 is supplied to one of a pair of sliding contacts 114 which are mounted to rotate with the hollow shaft 73 of drum 7d. The current is fed from the commutator through the hollow shaft by means of :a conduotor 116 to a terminm board 118. The terminal board carries a plurality of common terminals 120 and each of the heat generating cartridges 32 in jaw members fill are connected to one of the common terminals by means of suitable conductors 122 which supply the current for generating heat. The circuit through the cartridge is completed by conductors 124, common terminals 126, conductor 128 and the commutator brush 130.

it will be understood that there are ten complete circuits (not shown) one for each of the ten heart sealing jaw members of drum 7 5. All of the circuits from the commutator brushes to the cartridges are protected by enclosure (not shown) in the hollow shaft and drum. The heat generating cartridges 8?. may be readily installed in the jaw members and connected to the wires which are mounted in stationary position at each station on the drum. Since each heat generating cartridge is connected in parallel across conductors 116 and 128 the supply of power is the same for each insert and since the inserts are made to close tolerances the heat generated by each insert is approximately the same. As a result a single conventional temperature control element 130 connected to one of the heat generating cartridges may be employed for controlling the heat of all ten jaw members for sealing the thermal plastic liner in the longitudinal fin. The temperature control element is connected to the control box 112 by means of conductors 132 and 13 3 and commutator brushes 136 and 138 and conductors 139 and 140.

After the thermoplastic liner in the longitudinal fin of the bag tube is sealed the bag tube is transferred to drum 103 where it is prepared for the next heat sealing operation. As indicated at 14-1 drum 168 is provided with four stations (PEG. 1) each of which is adapted to take a bag from each of the five stations on the fin sealing drum 7 ii. The four stations are spaced an equal distance apart around the circumference of drum. 1% and the speed of rotation of drum 108 is controlled in conventional manner so that the peripheral speed of the drum is approximately equal to that of drum 76.

As best shown in FIG. 8 a pair \Otf gripping fingers 142 are mounted for rotation in each station in a bearing block 143 which is secured by conventional means as by a set screw (not shown) in any desired position in a slot 144 in drum 1%. A spring 145 mounted at one end on a bolt 146 in the drum is connected at the second end to an arm 147 of the gripping fingers 14 2. Spring 145 exerts constant tension urging the gripping fingers 142 to close against the surface of drum H38. Opening and closing of fingers M2 is controlled by arm 148 and cam follower 1459 which is pressed against cam rail 150 by the spring 145. As fingers 142 advance into the pick up point at the bottom of drum 1% the fingers are open ready to receive end flap 38 of the bag tube which is fed in under the open gripper. Cam arm 148 then rides down the depression 152 in cam rail 15% and spring 145 causes the gripping fingers to close on flap 38 whereupon the heat sealing jaw members 80 open and the bag tube proceeds to travel with drum 1% where it is held in position by fingers 142.

Referring to FIGS. 1 and 5 it will be understood that cam rail 1% is provided with an incline (not shown) adapted to open jaw members 8% for release of the bag tube to drum 1% and cam rail 1% is also provided with suitable camrning surfaces (not shown) to tilt jaws St) to avoid contact with drum 1% in the manner previously described hereinabove in connection with drum 48. The most efficient transfer of [the bag tube occurs when drum 1% is so mounted that a single vertical plane may be ipassed through the center of both drums 76 and 1% and when fingers 14-2 are caused to close when the gripping surface is centered on such vertical plane.

As the bag tube is carried along on drum 1th; longitudioa'l fin 72 projects out from the exposed surface of the tube (FIG. 8) in position between a pair of hollow guide tubes 154. Guide tubes 154 assist in holding the body of the bag tube adjacent the surface of drum 1% and each tube has a plurality of small holes 156 which direct a stream of air at the longitudinal fin to cool the fused plastic liner. Air is supplied to the tubes 154 by any convenient means (not shown). t

As the bag tube approaches the top of drum 198 the fin passes under a fin flattening wire 158 (FIG. 10), which is arranged at an angle to cont act the fin and flatten it down as the fin passes under the wire which is sloped downwardly toward the surface of the A pair of guide members 16% located on opposite sides of the fin flattening wire assist in holding the bag tube flat against the surface of drum 108.

Drum 168 is provided with a pan of jaws 162 located under the leading end portion of the bag tube in position to grip the tube at score line 44 which marks one side of the end closure of the bag and a similar pair of jaws 164 are located to the rear in position to grip the body of the tube and end closure of the bag along the score line 44 which marks the second side of the bag end closure (see FIG. 20).

As best shown in FIGS. 8 and 10 the two pairs of jaws 162 and 164 are of identical construction and each is provided with one stationary jaw member 166 and a cooperating movable jaw member 165 pivotally mounted on a stub shaft 170. The movable jaw member carries an arm 172 which mounts a spring 173 held under constant tension to urge the movable jaw to close against the stationary jaw. Red 174 mounted to reciprocate in a suitable bearing 176 controls the opening and closing of the movable jaw member and for this purpose rod l74 has a cam follower 177 which rides on the cam 178. In the preferred form of structure shown the bearing 176 and the shank of rod 174 carried by the bearing are square in order to prevent rotation of rod 17d and keep the cam follower properly oriented on cam rail 178.

The bag tube is tucked down in between the jaws 162 and 164 by means of a pair of tucking blades 1% and 182 respectively (FIGS. 1U, 11, and 12). Each tucking blade is of identical construction and each blade is mounted on a generally rectangular block 184 which has a pair of stub shafts 186 at each end that are pivotally mounted in a pair of arms 13%. Each end of the rectangular block fits into an opening 1 in arm and there is a small space between the rectangular block and side walls of the opening 189 to permit the block to pivot a limited amount relative to the arms. Arms 188 are mounted in fixed position on shaft 1% which rotates in counterclockwise direction (FIG. 10) and the rotation is so timed that a tucking blade enters the space between each pair of jaws 162 and 154 on transfer drum H38.

A stripper plate 192 is mounted at the bottom of block 184 adjacent the tucking blades by means of bolts 193 which are slidably mounted in the block 184. Compression springs 194 press against the plate to urge it to move away from the block. The head of bolts 1% are thereby caused to bear against the rectangular block and limit movement of plate 192 away from the block.

Jaws 162 and 164 are open as they approach the top of drum 1G8 and the tucking blades are so adjusted that the blades enter down into the space between the jaws to tuck a portion of the bag tube along the score lines 44 down in between the jaws. As the tucking blades move down into the jaws the stripping plate 1% contacts the bag tube on the surface of drum 1% and continued rotation causes the plate to move upwardly toward the bottom surface of block 184. The tuck is completed when the clamping surface of the stationary jaw res is approximately in a vertical plane through the diameter of drum 108. At this time the movable jaw member 163 is closed against the stationary ja-w 166 by spring 173 as the cam follower 177 rides down the depression 1% on cam rail 178. The jaw grips the tuck of the bag tube under the pressure of spring 173 and continued rotation of drum 103 and shaft 1% results in separating the tucking blade 1% from jaw 162. Since the tucking blade and the line of contact between the two jaw members move out of the line of a vertical plane through the diameter of drum 1%, the grip of the jaws on the tucking lads will cause the blade and its housing to pivot on the stub shafts res and this makes it possible to move the tucking blade out from between the two jaw members without disturbing the position of the tuck of the bag tube between the jaws. The spring loaded stripping plate 1% assists in keeping the tuck of the bag tube between the jaws as the tucking blade is separated from the jaws and spring rat causes the plate to move down away from block 184- to strip the tuck of bag tube from the tucking blade and hold it pressed down in between the two jaw members. At the jaws is controlled by means of arm 218.

time the first tuck is made in the bag tube the longitudinal fin is held fiat against the end closure of the tube by the fin flattened Wire 3158 and since the flattened fin is tucked between jaws 162 it is held flat by these jaws while the second tuck is formed in the tube. The second tuck is formed in the bag tube by jaw 164 and tucking blade 132 in the same manner described for the first tuck. As shown in FIG. 13 the two tucks in the bag tube which are positioned at opposite sides of the end closure cause the two end fiaps '33 and 39 to stand upright on the surface of drum ltlfi. Rotation of the drums 76 and 1th: and tucking blades 13% and 1.32 is synchronized in conventional manner by conventional means not shown to provide each of these with the same peripheral speed to effect the transfor of bag tubes from drum 76- to 108 and the tucking operation performed by the blades.

Drum H 8 continues to rotate until end flap d8 is approximately in a horizontal plane through the diameter of drum 1%.? and then heat sealing jaws 1% and 198 mounted on drum 2% (PEG. l3) clamp the respective flaps to seal and fuse the thermoplastic liner across the end flaps of the bag.

Referring to FIG. 1 drum Ztltl has five stations as indicated at 2&1 each of which is adapted to receive a bag tube from drum 108. Drum 2% continuously rotates in clockwise direction (FIG. 13). For the most efficient transfer of bag tubes drum 2% is so mounted that a single horizontal plane may be passed through the center of both drums 168 and 2%.

The detailed construction of the heat sealing jaws for the end flaps is shown in FIGS. 13 and 14. Since the heat seal across the end flap is positioned a substantial distance inwardly away from the edge of the flap, the heat sealing jaws must be wide open in order to clamp the end flap adjacent the line of the tucks in jaws 162 and 164. 'In the form of construction shown the angle between the two jaw members when fully opened is about ninety degrees (see FIGS. 13 and 15).

Heat scaling jaw 1% which clamps end flap 35 of the bag tube comprises a stationary jaw member 2522 and a movable jaw member 2%- Which is in position to lead the stationary jaw in the direction of rotation of the drum. The movable jaw member 204 is pivotally mounted on by means of a pair of links 2% which are in turn pivotally mounted on stub shafts Ztlfi on the stationary jaw. A second pair of links 210 are rotatively mounted at one end on the movable jaw as at 211 and the second end of links 21%} are pivotally connected to one end of arms 212 which at their second end are keyed to a shaft 214. The connection of link 21% with arm 212 forms a toggle joint so that these two members are substantially in a straight line when the movable jaw member is closed against the stationar jaw member as shown in PEG. 13. When the jaws are open the toggle point is buckled in the direction of the arrow in FIG. 13 to open the jaws and form an angle of approximately ninety degrees between them as shown in FIG. 15. The toggle action of the link and arm provides very rapid and positive opening and closing of the jaw members and because of the toggle action of the links only a small spring force is necessary to provide a high gripping pressure. A pair of springs are on shaft 214 (FIG. 14) constantly urge shaft 21 to rotate in clockwise direction (PEG. 13) to close the jaw members. The opening and closing of the One end of arm 218 is keyed to shaft 214 and the second end of the arm carries a cam follower 220, which rides against the stationary cam track 222.

Heat sealing jaw 19% is of similar construction to that of heat sealing jaw 1%. In the case of jaw 198 the leading jaw member 224 in the direction of rotation (FIG. 13) is the stationary jaw and the movable jaw memher 226 is the trailing jaw member. The movable jaw member 226 is pivotally mounted by links 223 which are pivotally mounted at their second end on stub shafts 230 of the stationary jaw member. A second pair of links 232 are rotatively mounted at one end on the movable jaw member as at 234 and the second end of links 232 are pivotally mounted at one end of a pair of arms 236 which are in turn keyed to a shaft 238. An arm 23:9 keyed to shaft 238 has a cam follower 249 which rides against the stationary cam track 242. A pair of springs (not shown) are mounted on shaft 238 in identical manner to the springs of jaw 204 and the springs constantly urge shaft 238 to rotate in counterclockwise direction (FIG. 13) to close the jaws and exert gripping pressure against the stationary jaw member. Pivotal arm 236 and link 232 provide the same toggle action as links 210 and 212 of the heat sealing jaw 196.

Rotation of drums 1G8 and 260 is synchronized in conventional manner by conventional means (not shown) to provide the same peripheral speed on both drums so that as end flap 38 is moved into position approximately in a horizontal plane through the diameter of drum 1% the line of contact between the two jaw members of heat sealing jaw 196 when closed will also lie approximately in the same horizontal plane with end flap 38. When the heat sealing jaw 1% approaches the horizontal pick up position the two jaw members are open and at the pick up position cam fol-lower 225 on track 222 moves outwardly toward drum 108 (FIG. 13) so that springs 216 will rotate shaft 214 and arm 212 in clockwise direction (FIG. 13) to close the movable jaw member 294 over against the stationary jaw 2%2 and grip flap 38 with the clamping pressure provided by the springs. At this time jaw 162 is opened as cam follower 177 rides down on an incline (not shown) on cam rail 17%.

Drums 198 and 260 continuously rotate and when the second end flap 39 of the bag tube is in the pick up position the movable jaw member 226 is closed against the stationary jaw member 224 when the cam follower 24% on the pivotal arm ass rides down the incline 248 on cam track 242 to rotate the pivotal arm in counterclockwise direction, HG. 13, and cause the heat sealing jaw 19% to grip end flap 39. law 164 on transfer drum 1% is opened in a manner described for jaw 162 after the heat sealing jaw 1% is closed on the end flap 39.

Cam tracks 222 and 242 and the inclines in the cam tracks for closing the jaws are for convenience of illustration set off to one side of the jaw members in an arbitrary position. In the operative machine the inclines in the cam tracks will be so located as to close the jaw members as described hereinabove.

The heat sealing jaws 1% and 198 are each provided with conventional heat sealing elements 249 which are supplied with electricity for generating heat preferably in the manner previously described for the heat sealing jaws 85 on drum 75. As drum 2% continues to rotate the pressure and heat of the jaws fuse the thermoplastic liner in the end flaps to complete the seal in the end closure of the bag tube and make it sift proof. The pressure and temperature employed is the same as that specified for the heat sealing jaws 8b which seal the thermoplastic liner in the longitudinal fin.

The heat sealing jaws 1% and 1% carry the bag tube through an angle of approximately two hundred and seventy degrees until a line through the center of the space between the two jaws is approximately in a vertical plane through the diameter of drum 2% whereupon the bag tube is transferred to a final drum 250 which is adapted to fold and paste the end flaps down to finish the bag structure. The pasting and folding down of the end flaps to complete the finished bag may be carried out in conventional manner with conventional equipment. In accordance with the present invention, a preferred form of apparatus used for completing the end closure of the bag is shown which employs the rotating drum 256 illustrated in the drawings.

lid

Rotation of drums 25b and 266 are synchronized in conventional manner by conventional means (not shown) to provide the drums with the same peripheral speed to effect transfer of the bag tubes and as before most effective transfer is achieved by so mounting drum 25f) that a single vertical plane may be passed through the center of both of the drums 2% and 250. As illustrated in FIG. 1 drum 259 is provided with two stations as indicated at 251 each located ninety degrees apart on the drum. The drum 2.59 continuously rotates in counterclockwise direction (FIG. 1) and rotation of drum 250 is synchronized with the clockwise rotation of drum 2% so that a station of drum 2% is in position to pick up a bag tube from each of the stations on drum 260. As illustrated in FIG. 16 each of the stations on drum 25b is provided with a pair of conventional grippers 252 each located on opposite sides of the drum. As illustrated in FIG. 15 the grippers are made to fit into the space between the heat sealing jaws 1% and 198 of drum 2%. When the bag tube has been advanced into the pick up position by drum 2% conventional cams customarily used in paper bag machines actuate grippers 252 to swing in between jaws 1% and 198 below the bag tube whereupon the grippers press the body of the end closure against the surface of drum 25%. At the same time follower 229 engages the stationary cam track 222 (not shown) which causes arm 213 to rotate in counterclockwise direction (FIG. 13), to open the heat sealing jaw 1% and cam follower 24% engages the stationary cam track 242 which causes arm 236 to rotate in clockwise direction and open jaw 198. The bag tube is then carried by grippers 252 on drum 25%. in this connection it will be understood that the stationary cam tracks 222 and 242 hold jaws 1% and 198 open until the jaws are again closed to receive a bag from drum 1&8.

In order to more firmly grip the bag tube on drum 25:) a second pair of conventional grippers 25% having two fingers positioned on opposite sides of the drum (FIG. 15) are actuated by conventional cam means to rotate in over the end closure and press it inside the score lines 44 against the surface of drum 259. As a result opposite sides of the end closure of the bag tube are each firmly held in fixed position on drum 25% by three gripping fingers and the end flaps 38 and 39 project up above the surface of the bag tube because of the sharp crease line formed by the tucking jaws 162 and 264. It will also be noted that the sharp crease line formed by the tucking jaws along the score lines 4-4 cause the longitudinal fin to lie substantially flat down against the surface of the end closure of the bag tube.

The next step is to apply conventional adhesive to the end closure for pasting down and sealin the flaps. This is done by a conventional roll 26f (FIGS. 1 and 18) which contacts the end closure to apply adhesive in the generally horseshoe shaped pattern shown in FTG. 18. Since the end flaps project upwardly away from the periphery of drum 250 a shoe 262 pivotaily mounted at 261 is actuated in conventional manner by suitable cams (not shown) to swing in against the leading end flap 3% and flatten it against the periphery of drum 2% so that it will be fed in orderly manner in between rolls 2% and ass. Otherwise the end flap 3% might be folded over and the paste would not be applied in the desired pattern. Suitable guide wires 265 are provided to hold the end flaps down as the bag is fed in under the adhesive applying roll 260.

After the adhesive is applied the rear or trailing end flap 39 is folded down and pressed against the body of the end closure where it is securely held by adhesive.

This is done in conventional manner by a rod 2% mounted at opposite ends in a pair of chains 256. The chains and rod are rotated in clockwise direction by gears 268, 269 and 2'70 (PEG. 19) at a speed greater than that of the bag tube and as a result the rod overtakes the end closure to contact the rear flap and fold it down 

1. THE METHOD OF FORMING A CLOSURE IN ONE END PORTION OF A BAG TUBE HAVING TOP AND BOTTON WALLS SEPARATED BY A GUSSET WALL AT EACH SIDE WITH HEAT FUSIBLE MATERIAL AT LEAST POSITIONED ON INNER SURFACE PORTIONS OF SAID END PORTION OF THE BAG TUBE WHICH COMPRISES THE STEPS OF ADVANCING A LENGTH OF BAG TUBE IN THE DIRECTION OF ITS LENGTH, SLITTING AT LEAST ONE WALL IN SAID END PORTION TO FORM A FLAP THEREIN, GRIPPING THE FLAP, FOLDING THE SECOND WALL IN SAID END PORTION BACK AWAY FROM THE DIRECTION OF TRAVEL TO FORM AN ANGLE BETWEEN ADJACENT OVERLAPPED SURFACES OF SUCH WALL AND AN OPEN BOX WITH UPSTANDING SIDE WALLS, AND THEN WHILE THE FLAP IS HELD IN A DEPRESSED POSITION, COLLAPSING THE BOX BY FOLDING THE OPPOSITE UPSTANDING SIDE WALLS DOWNWARDLY INTO THE INTERIOR OF THE BOX TO BRING THE INTERIOR OF OPPOSITE END PORTIONS OF SAID SIDE WALLS INTO FACE TO FACE CONTACT TO FORM AN UPSTANDING LONGITUDINAL FIN AND TO POSITION A PORTION OF THE INNER SURFACE OF SAID SIDE WALLS ADJACENT BOTH SIDES OF THE FIN IN OVERLAPPING RELATIONSHIP WITH PORTIONS OF THE INNERSURFACE OF THE 